Backhaul Technologies : Mobile versus fibre solutions

Technically, fibre is a near perfect backhaul medium to cater to the growing data traffic on operator networks. Most operators in Europe and North America have over 50 per cent of their cell sites connected through fibre, while 80 per cent of towers in the US, China and Korea are backhauled on fibre. The situation in India is completely different with fibre penetration at a mere 20 per cent. There are several operational and financial challenges that have prevented operators from rolling out robust fibre networks. Fibre installation is expensive, especially in Tier I and metro cities. Further, securing right of way (RoW) is a big hurdle, which has increased operator dependence on microwave backhaul over time. Currently, the majority of the telecom network in the country is based on microwave backhaul - nearly 80 per cent of cell sites have a microwave-based backhaul link. That said, sector dynamics have undergone a fundamental change in terms of growth drivers and with data becoming central to operators’ growth and business, there is an urgent need to strike a balance between the growing backhaul requirements and available channels. Deploying fibre in the backhaul will become unavoidable as 4G subscriptions grow.

tele.net takes a look at the changing mobile-fibre backhaul mix…

Improving share of fibre

Given the virtually unlimited capacity and extensive reach of fibre, it is undoubtedly a notch above microwave in terms of meeting backhaul requirements. The industry has started witnessing a major shift in the microwave-fibre backhaul mix, particularly for large operators as many of them are moving their metro backhaul to fibre. As per industry reports, the fibre-to-microwave ratio has started shifting for some operators from 1:5 to around 1:2. Further, Wi-Fi hotspots, which are now being considered as a key mode of data offloading, also require fibre backhaul networks for carrying traffic. Moreover, operators in India have started warming to the idea of backhaul sharing and are exploring ways to share fibre. This will result in more fibre per operator to be deployed in the backhaul. Further, with 4G gaining traction, a robust fibre-based backhaul will become a must for operators to support seamless delivery of high-speed data services.

Microwave-based backhaul is here to stay

The growing share of fibre in the backhaul mix, however, does not imply that operator dependence on microwave will decrease. It will continue to be a critical component in operator networks in the near term until fibre connectivity becomes widely available.

The capability of microwave link-based backhaul has improved significantly in recent years owing to innovations in microwave technology, such as the use of multiple antennas and higher order modulations. As per industry estimates, microwave backhaul links are capable of supporting up to 200 Mbps of data on an average, which at present is sufficient for operators given their traffic flow. Moreover, microwave technology provides impressive long-haul capacity that can be measured even in gigabits and is often enough for backhaul implementations.

Besides, microwave is more flexible as a microwave site can be easily moved or redirected to accommodate changes in network traffic. These changes can be carried out within a span of a few days or weeks, and on a regular basis since microwave is cost-effective. Even in terms of reliability, microwave scores over fibre, which is more vulnerable to damage.

Determining an optimum mix

Of late, operators have started deploying a hybrid of microwave and fibre in secondary routes and connecting a growing number of sites through fibre to meet bandwidth and latency requirements.

Going forward, reaching at an optimum mix of both mobile and fibre-based backhaul systems would be crucial for operators to prevent a traffic logjam on their networks. Interestingly, microwave’s capacity limitation as compared to fibre will not be a key factor in determining this mix. Instead, the decision will be influenced by the availability/presence of fibre and the cost of ownership. The quantum of spectrum available for long term evolution services will also be a key factor in determining the right mix of backhaul technologies.